Researchers have found extraordinarily high rates of trauma exposure and posttraumatic stress disorder (PTSD) symptoms in adults living in low income, urban environments, and increased risk for PTSD as an adult associated with a history of childhood abuse.

The researchers, reporting in the March 19, 2008 Journal of the American Medical Association, also found variation in a gene associated with biological responses to stress (FKBP5) predicts risk for PTSD among survivors of child physical and sexual abuse.

One of the most important questions about PTSD is why, given the same level of adult trauma, some people develop severe PTSD symptoms, while others appear to be more resilient and recover.

"Individuals with PTSD are at least 7 percent to 8 percent of the U.S. population, but we see strikingly higher rates in some groups," says Dr. Bradley. "The data from this study suggest that adults living in high violence areas show PTSD rates that are at least as high as those found among recently returned combat veterans."

In a study funded by the National Institute of Mental Health (NIMH), researchers compared the level of PTSD in adults who were abused as children to adults who were exposed to trauma without child abuse. They also looked at the genetic variations in the gene FKBP5, which is related to the stress response system.

From 2005 to 2007, screeners approached patients in the waiting room of primary care or obstetrical-gynecological clinics of Grady Memorial Hospital, a large urban hospital in Atlanta. The patients were asked to complete a battery of self-report measures including a traumatic events inventory and a childhood events questionnaire. They were also asked to provide a saliva sample for DNA. There were 900 patients who participated in the study.

"The study data confirms that childhood sexual and physical abuse occurs at disturbingly high rates, and is a major public health issue resulting in increased risk for PTSD in a significantly large population," explains Dr. Bradley, who is also the director of the PTSD program at the Atlanta Veteran's Affairs Medical Center and co-director of the Grady Trauma Project.

"Additionally, the data from the DNA samples implies that heritable factors in combination of exposure to childhood abuse are associated with changes in developmental, biological processes involved in how individuals may respond to traumatic events," she says.

Researchers hope that the important pieces of information resulting from this study and future studies will eventually translate into prevention of this growing mental health epidemic.

Co-author of the study is Elisabeth B. Binder, MD, PhD, Department of Psychiatry and Behavioral Sciences and Department of Genetics at Emory University, and Institute of Psychiatry, Max Planck Institute, Germany. Corresponding author is Kerry J. Ressler, MD, PhD, Howard Hughes Medical Institute, assistant professor, Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine and researcher, Yerkes National Primate Research Center.